Description of problem:
In F22, when I click on "Write image" button, the progress goes immediately to 100% and says Finished, in a single second. No data could have been obviously written. This happened to me every time, trying different ways (download and write, pick an existing iso), in a VM and on bare metal.
No useful information is written anywhere, stdout, journal, nothing.
Version-Release number of selected component (if applicable):
liveusb-creator-3.93.1-1.fc22

When trying liveusb-creator-3.93.2-1.fc22, I received an error at the end of the writing process:
[gui:209] 'NoneType' object is not callable
Traceback (most recent call last):
File "/usr/lib/python2.7/site-packages/liveusb/gui.py", line 205, in run
self.ddImage(now)
File "/usr/lib/python2.7/site-packages/liveusb/gui.py", line 215, in ddImage
self.live.dd_image(self.update_progress)
File "/usr/lib/python2.7/site-packages/liveusb/creator.py", line 400, in dd_image
update_function(1.0)
TypeError: 'NoneType' object is not callable